Inkjet printed images with wettable, fusible toner

ABSTRACT

Production of a permanent ink-jet image with a fusible, wettable, colorant-containing toner and ink-jetted clear fluid.

FIELD OF THE INVENTION

The present invention relates to ink-jetted clear fluids in combinationwith a toner with both colorant and hydrophilic polymers to produce apermanent ink-jet image. In particular, this invention relates to an inksystem that utilizes the addition of specific toner/developerscomprising hydrophilic polymers as well as colorant, with aqueous basedink-jet clear fluids. These dual systems produce a permanent image thatis resistant to image degradation factors such as mechanical abrasion,light, water, and solvents such as the ones used in highlighter markers.

BACKGROUND OF THE INVENTION

Along with the computerization of offices in the 1980's cameelectronically controlled non-impact printers such as the ink jet andlaser printers. Drop-on-demand inkjet printers can be piezo or thermal(bubble jet). In piezo ink jet systems, inkjetted droplets are ejectedby an oscillating piezo crystal. However, the thermal ink jet dominatesthe drop-on-demand office ink jet market. In this system, rapid heatingbehind the inkjet nozzles cause a bubble of vapor to form in the fluidthat is inkjetted. The resulting bubble expansion and fluid ejectionfrom the inkjet printer cartridge causes printing to appear on thesubstrate.

Full-color inkjet printers are more common than color lasers and aremuch more economical. The main advantage of inkjet printers over lasersand other non-impact printing techniques include their low cost andsimplicity. Thermal inkjet systems are capable of dispensing fluidrapidly and accurately. The technology of this and other inkjet systemsare discussed in the Chemistry and Technology of Printing and ImagingSystems, edited by P. Gregory, published by Chapman & Hall, 1996.Representative thermal inkjet systems and cartridges are discussed inU.S. Pat. No. 4,500,895 to Buck et al., U.S. Pat. No. 4,513,298 toScheu, and U.S. Pat. No. 4,794,409 to Cowger et al., which are allhereby incorporated by reference.

The technology of inkjet printers has undergone many changes andimprovements since they first appeared. Research has been conducted toensure that the images produced are of consistent high quality. Thus, itis important that the images be permanent by being waterfast, smearfast,smudgefast, run-fast, and the like when exposed to chemical ormechanical abrasion. Non-smearing of the image when portions of theprinted page are highlighted with colored markers is of particularinterest. Oftentimes, the image produced by the inkjet printer on paperis not satisfactorily fixed and smears, blurring the printed image whensubjected to highlighting. This type of image is not regarded aspermanent.

Image permanence is defined as transference of color from the substratewhen the image printed thereon is subjected to chemical and mechanicalabrasion. Highlighting is oftentimes the form of chemical and mechanicalabrasion experienced. This transference of color is measured by opticaldensity (mOD). More permanent images have lower milli-Optical Density(mOD) values.

Another desired feature of printed images is light fastness. As usedherein, light fastness will mean that the images do not fade whenexposed to light. Light fastness is another measure of permanence asused herein. Light fastness is measured by exposing printed images tointense light in light chambers (fadometers) and comparing print densitybefore and after the exposure.

There have been many past attempts at improving the permanence ofwater-based inkjet printing systems. Included among these attempts areU.S. Pat. No. 5,549,740 to Takahashi et al., U.S. Pat. No. 5,640,187 toKashiwakazi et al., and U.S. Pat. No. 5,792,249 to Shirota et al. whichutilizes an additional or “fifth” pen to apply a colorless fluid on tothe substrate. As will be seen in the comparative testing, the mODvalues for the images printed thereon are quite high.

Another printing technology that is inherently more permanent thanwater-based inkjet are hot-melt inks. These materials are solid at roomtemperature and are similar to wax crayons. The colorants used in thesematerials are solvent dyes that are soluble in the ink vehicle orpigment dispersions. Like laser toners, these materials are incompatiblewith the fluids used in inkjet printing.

U.S. Pat. Nos. 5,817,169 and 5,698,017, both to Sacripante et al.,disclose hot melt ink compositions which use oxazoline as a vehicle usedfor the colorant in a nonaqueous, hot melt inkjet ink. One of theadvantages of this technology is that the waxy nature of the hot meltink creates images that are more waterfast and may be successfullyutilized on plain papers. This technology is in contrast with the instant invention, which utilizes an ordinary aqueous four-color ink penset.

Another highly efficient printing system in common use currently islaser printers. In a laser printer or copier, light from a laser beam isused to discharge areas of a photoreceptor to create an electrostaticimage of the page to be printed. The image is created by the printercontroller, a dedicated computer in the printer, and is passed to theprint engine. The print engine transcribes an array of dots created bythe printer controller into a printed image. The print engine includes alaser scanning assembly, photoreceptor, toner hopper, developer unit,corotron, discharge lamp, fuser, paper transport, paper input feeders,and paper output trays.

The final stage of laser printing or copying is to fix toner onto thepaper. Toner is very fine plastic powder that is transferred from thephotoreceptor. Once transferred from the photoreceptor, it lies on thepaper in a very thin coating with nothing to hold it in place. In orderto fix the toner to the paper, it is heated by passing between a pair ofvery hot rollers, so that the plastic melts around the fibers of thepaper and is “fused” into place. The image is now fixed permanently ontothe paper.

The fuser of a typical laser printer is of particular interest to theprinting system of this invention. In these systems, fusing or meltingthe polymeric resin in which the colorant is embedded converts thediscrete toner particles into an amorphous film. This film becomes thepermanent image that results in electrophotographic copy or laserprinted copy. However, the laser printer toners are incompatible withwater. Since most inkjet materials are water-based, it is not possibleto use laser toners in inkjet printers, and, therefore, Inkjettechnology has not yet found a way to make the printed image permanent.

U.S. Pat. No. 4,943,816 to Sporer, discloses the use of a dye-less fluidfor latent imaging. The dye and ink are omitted and a colorless markingfluid is used to create a latent image to be developed in a subsequentstep. Omitting the dye is believed to prolong the printhead life.

U.S. Pat. No. 4,312,268, to King et al., describes a mechanical transferof clear or colored toner to a wet image. The mechanical transfer is notby electrostatic transfer. The powdered material adheres to the wetsurfaces and the rest falls down into the housing.

U.S. Pat. No. 5,847,738, to Tutt, describes the application of a totalovercoat over inkjet prints as a separate process in a sequentialfashion.

Accordingly, a need remains for a printing system using water-basedinkjet technology, yet, will produce permanent laser-like images. Thesepermanent images will be consistent and stable with respect to a varietyof printed substrates. An ideal situation would be combining theconvenience and safety of aqueous inkjet inks with the permanence ofelectrophotographic copies. The present invention satisfies this in aunique manner, which is described herein.

SUMMARY OF THE INVENTION

The present invention relates to a method for creating a permanentinkjet image comprising:

-   (a) ink-jet printing a clear fluid onto a substrate;-   (b) exposing said substrate from (a) to a toner comprising colorant    and hydrophilic polymers.    The present invention further relates to a method for creating a    permanent inkjet image comprising:-   (a) exposing a substrate to a toner comprising colorant and    hydrophilic polymers;-   (b) ink-jet printing a clear fluid onto said substrate from (a).

The present invention also relates to an image on a substrate comprisingdiscrete areas of inkjetted clear fluid and electrostatic tonercomprising hydrophilic polymers, the image being fused onto thesubstrate and discrete areas substantially free of said inkjet ink andelectrostatic toner.

The present invention additionally relates to a printing systemcomprising:

-   an inkjet printing engine for inkjetting clear fluid;-   a developer mechanism for applying electrostatic-toner comprising    hydrophilic monomers;-   a charging unit; and-   a fuser.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 is a schematic of the printing method according to the presentinvention.

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENT

As can be seen in FIG. 1, the following steps are utilized, combininginkjet printing and electrostatic toners to produce a permanent imagewithout altering the feel or coating on the rest of the substrate. Thus,discrete areas of the substrate contain ink and toner and discrete areasare substantially (cannot be visually or tactually detected with thehand) free of ink and toner.

Charging the Media

The media is preferably charged to a given polarity prior to printing.In the charging step, the media is covered with ions of a selectedpolarity using a high voltage wire, grid, or charge roller. The mediashould have the same polarity as the toner/developer material. Usefuldevices for charging the media include the use of a scorotron or acorotron. Charging the media is well known in the art ofelectrophotography. See U.S. Pat. Nos. 4,478,870; 4,423,951, and4,041,312, hereby incorporated by reference.

Inkjet Printer

Ink-jet printing is a non-impact printing process in which droplets ofink or other fluid are deposited on print media, such as paper,transparency film, or textiles. Ink-jet printers are generally lower incost and offer high quality output compared to other types of printers.Ink-jet printing involves the ejection of fine droplets of ink or otherfluid onto print media in response to electrical signals generated by amicroprocessor. In a general embodiment of the present invention, theinkjetted fluid is a clear fluid containing no colorants. Two optionsfor achieving fluid droplet ejection in ink-jet printing are: thermallyand piezoelectrically. In thermal ink-jet printing, the energy for dropejection is generated by electrically-heated resistor elements, whichheat up rapidly in response to electrical signals from a microprocessorto create a vapor bubble, resulting in the expulsion of ink or otherfluid through nozzles associated with the resistor elements. Inpiezoelectric ink-jet printing, the droplets are ejected due to thevibrations of piezoelectric crystals, again, in response to electricalsignals generated by the microprocessor. The ejection of droplets in aparticular order forms alphanumeric characters, area fills, and otherpatterns on the print medium.

Ink-jet printers and inkjet print engines are well known in the art.Representative thermal inkjet systems and cartridges are discussed inU.S. Pat. No. 4,500,895 to Buck et al., U.S. Pat. No. 4,513,298 toScheu, and U.S. Pat. No. 4,794,409 to Cowger et al., which are allhereby incorporated by reference.

Developing Mechanism

The toner in a preferred embodiment herein is a dry toner having athermoplastic binding component. Other components may be added to thetoner formulation to enhance certain properties or performancecharacteristics of the toners. These include additives to control therate and level of charge and additives for enhancing flow. Oil issometimes added in the fusing process to inhibit adhesion of the tonerto the fuser rollers.

In a preferred embodiment of this invention, the toner is selectivelyattracted to the inkjetted fluid on the media surface, which has actedto neutralize the polarity or charge on the media. The media may beeither positively or negatively charged, and the toner system similarlyshould contain the same charge. In the transfer step, media, most oftenin the form of a sheet of paper, is given an electrostatic charge thesame as that of the toner, the media is then subjected to inkjettingwhich causes the areas exposed to the inkjetted fluid to lose itscharge. The media is then passed along in close proximity to thedeveloper surface to transfer toner and, consequently, the toner istransferred only to the areas exposed to inkjetted fluid. Followingtransfer of the toner, the media is passed between a pair of fuserrollers. The pressure and heat of the rollers fixes the toner in themedia.

In a preferred embodiment of this invention, the developing mechanismthat acts to transfer the toner may consist of a charged roller, a cleartoner hopper, stirrer, wiper blade, and a source of AC/DC voltagebiases. The toners or precursors used in this invention are polymers,charge control agents, stabilizers, and other components typically foundin electrophotographic toners. Such polymers and materials arecommercially available from Clariant, Image polymers, Sybron, Zeneca andothers.

Among the properties of interest for application of some of thedeveloper polymers useful herein include glass transition temperature(Tg) and Melt Index (MI). As used herein, glass transition temperature(Tg) will mean the transition that occurs when a liquid is cooled to anamorphous or glassy solid. It also may be the change in an amorphousregion of a partially crystalline polymer from a viscous, rubbery stateto a hard or brittle one brought about by change in temperature. In thisinvention, the materials which are used to improve permanence of theimages produced by inkjet printing fluid have a Tg that may range fromabout 50 to about 180 degrees C. A more preferred range of glasstransition temperatures will range from about 50 to about 90 degrees C.Melt index (MI) values for the instant materials may range from about400 to about 3000 grams/10 minutes. A more preferred range may be fromabout 1800 to about 2500 grams/10 minutes. A still more preferred rangeis from about 2000 to about 2250 g/10 min.

Presented herein are representative examples of syntheses of fusible,wettable polymers that provide permanence to the images formed by thematerials and processes of the instant invention. Examples of suchfusible, wettable polymers are (but they are not limited to): ˜5000 MWChitosan lactate, polyacrylic acid, PolyStyrene-Maleic Anhydridederivatives, Rosin-Maleic anhydride derivatives, PolyAbiatic acidderivatives, polyamides, polyolefin-acrylates, and styrenatedpolyacrylates. Other non-limiting examples include polymers havinghydrophilic surface groups such as carboxylate, PEG, sulfonate,quatematry ammonium, and phosphonium. In a most preferred embodiment,the wettable hydrophilic polymers are water dispersible and have a sizeof from 5 to 10 microns.

A variety of colorants as described below can be used to produce colorin the toners.

Pigments—When a pigment is used as a coloring material in the inkcomposition of the present invention, the amount of pigment used iswithin the range from about 0.5 to about 20 weight percent. A morepreferable range of pigment ranges from about 1 to about 15% by weight,still more preferably is a range of from about 2% to about 12% by wt.

An example of a pigment used for black ink is carbon black. The carbonblack may be produced by either a furnace or channel method. The primaryparticle size of this material ranges from 15 to 40 μm, specific surfacearea is 50 to 300 m2/g, and has oil absorption from 40 to 150 ml/100 g,the volatile component is 0.5 to 10%, and the pH value may range from 2to 9. Examples of suitable commercially available carbon blacks includeNo. 2300, No. 900, MCF88, No. 33, No. 40, No. 45, No. 52, MA&, MA8, No.2200B, Raven 1255, Regal 400R, Regal 330R, Regal 660 R, Mogul L, ColorBlack FW1, Color Black FW18, Color Black S170, Color Black S150, Printex35, and Printex U.

In this invention, the black colorants that are employed include NovofilBlack BB-03, and Hostafine Black TS. The Novafil material is a pigmentthat is approximately 27% pigment dispersion based on anionic dispersingagents. It contains C.I. Pigment Black 7, carbon black and is anultrafine pigment dispersion suitable for all water based inkjetapplication. These pigments are available from Clariant Corp., Coventry,R.I.

Hostafine Black TS contains hydrophilic ultrafine pigment dispersionsbased on non-ionic dispersing and wetting agents. It contains carbonblack and has a pigment concentration of 33%.

Other black colorants, which may be used, include those listed in theColor Index and in Textile Chemist and Colorist reference publications.Water-soluble black colorants are commercially available from colorantvendors such as Cabot Corporation, Orient Chemical, and othermanufacturers. Surface modified colorants from these manufacturers areinitially water insoluble colorants which, by certain modifications, aresolubilized or stabilized as fine dispersions in water to preventagglomeration. See U.S. Pat. Nos. 5,707,432; 5,630,868; 5,571,311; and5,554,739 for a discussion of modified carbon black pigments and methodsof attaching functionalized groups to aid in their solubility.

Examples of pigments used for a yellow ink include C.I. Pigment Yellow1, C.I. Pigment Yellow 2, C.I. Pigment Yellow 3, C.I. Pigment Yellow 13,C.I. Pigment Yellow 16, C.I. Pigment Yellow 83, and the like. Examplesof pigments used for magenta ink include C.I. Pigment Red 5, C.I.Pigment Red 7, C.I. Pigment Red 12, C.I. Pigment Red 48 (ca), C.I.Pigment Red 48 (mn), C.I. Pigment Red 57 (Ca), C.I. Pigment Red 112,C.I. Pigment Red 122, and the like. Examples of pigments used for a cyaninclude C.I. Pigment Blue 1, C.I. Pigment Blue 2, C.I. Pigment Blue 3,C.I. Pigment Blue 15:3, C.I. Pigment Blue 16, C.I. Pigment Blue 22, C.I.Vat Blue 4, C.I. Vat Blue 6, and the like. Pigments whose performanceproperties are satisfactory when formulated for the present inventionare considered to be within its scope.

In the instant invention, colorants used include Hostafine Rubine F6Band Hostafine Blue B2G available from Clariant, Coventry, R.I.Hostafines are hydrophilic ultrafine pigment dispersions based onnonionic dispersing and wetting agents, available in all colors. In thisdisclosure, Hostafine Rubine F6B is magenta with a 40% pigment content.Hostafine Blue B2G is blue with 40% pigment as well. These colorants aremanufactured for suitability with water-based inkjet inks.

Any pigment, dye, or pigment-resin system available and compatible withthe other formulated ingredients of the fusible material of thisinvention may be used as colorants. An important factor that theformulator must keep in mind is thermal instability exhibited by certaintri- and tetrakis-azo dyes. Such thermal instability may lead tocharring of insoluble deposits (kogation), which is to be avoided.

Dyes—Dyes, whether water-soluble or water-insoluble, may be employed inthe practice of the present invention. Examples of water-soluble dyesinclude the sulfonate and carboxylate dyes, specifically, those that arecommonly employed in ink-jet printing. Specific examples include:Sulforhodamine B (sulfonate), Acid Blue 113 (sulfonate), Acid Blue 29(sulfonate), Acid Red 4 (sulfonate), Rose Bengal (carboxylate), AcidYellow 17 (sulfonate), Acid Yellow 29 (sulfonate), Acid Yellow 42(sulfonate), Acridine Yellow G (sulfonate), Nitro Blue TetrazoliumChloride Monohydrate or Nitro BT, Rhodamine 6G, Rhodamine 123, RhodamineB, Rhodamine B Isocyanate, Safranine O, Azure B, Azure B Eosinate, BasicBlue 47, Basic Blue 66, Thioflacin T (Basic Yellow 1), and Auramine O(Basic Yellow 2), all available from Aldrich Chemical Company. Examplesof water-insoluble dyes include azo, xanthene, methine, polymethine, andanthroquinone dyes. Specific examples of water-insoluble dyes includeCiba-Geigy Orasol Blue GN, Ciba-Geigy Orasol Pink, and Ciba-Geigy OrasolYellow.

The fixing fluid formulation comprises a colorant plus a vehicle. Atypical formulation useful in the practice of this invention includesone or more co-solvents, present from 0 to 50 weight percent, one ormore water-soluble surfactants, present in about 0.1 to 40 weightpercent, one or more high molecular weight colloids present in from 0 toabout 3 weight percent. The balance of the formulation is purifiedwater. One or more co-solvents may be added to the formulation of theink of this invention. Classes of co-solvents include, but are notlimited to, aliphatic alcohols, aromatic alcohols, diols, glycol ethers,polyglycol ethers, caprolactams, formamides, acetamides, and long chainalcohols. Examples of such compounds include primary aliphatic alcohols,secondary aliphatic alcohols, 1,2-alcohols, 1,3-alcohols, 1,5-alcohols,ethylene glycol alkyl ethers, propylene glycol alkyl ethers, higherhomologs of polyethylene glycol alkyl ethers, N-alkyl caprolactams,unsubstituted caprolactams, both substituted and unsubstitutedformamides, both substituted and unsubstituted acetamides, and the like.

In the present applicant's previous U.S. patent application Ser. No.09/629,784 filed Jul. 31, 2000, several fusible toner materials aredisclosed. Most of these toner materials are hydrophobic polymers andtherefore not “wettable”. They are present in electrophotography assmall, discrete grains that outline the image on a substrate prior tofusion. As such, these materials have been incompatible with and notviable for use in water-based inkjet inks. In contrast, among thefusible wettable polymers useable in the present invention, several arehydrophilic, wettable analogs of the hydrophobic toners taught in Ser.No. 09/629,784.

Fuser Mechanism

The printing system of this invention includes a printing apparatus thatis equipped with suitable heating means. Heat fusion is most often theway that the image formed by toner particles used in electrophotographyare fixed to the printed substrate. Most systems employ a heated rollerto fix the image although any other means of supplying heat is includedwithin the scope of this invention.

The heated roller is often a rubber roller impregnated with silicone oilwhich is preheated to about 90° C. It may also be a metal roller heatedwith incandescent light or a lamp equipped with a reflector. Certainlaser printers employ a ceramic heating element in the fusion stage.When the copier or printer is switched on, waiting time until themachine is ready to use is associated with heating the roller.

The heating means is designed to melt (or fuse) the toner on to thesubstrate. In high speed systems, flash fusion may be used. Flash fusioninvolves the use of heated lamps with a specific heat output are used torapidly heat the toner which then adheres to the substrate. Fusers arecommercially available from such companies that manufacture laserprinters such as Hewlett-Packard, Canon, Ricoh, and Panasonic. In allcases, the toner particles used in Electrophotography are hydrophobic.

A typical laser printer commonly available is the Hewlett-Packard LaserJet 4L Printer. In the fusing stage, toner is fused into the substrateby heat and pressure to produce a permanent image. The substrate(usually paper) passes between a ceramic heating element protected by athin Teflon sleeve and a soft pressure roller. This melts the toner andpresses it into the substrate. Other laser printers use a halogenheating lamp and require frequent warm-up periods to maintain a minimumstandby temperature.

EXAMPLES Example 1 Preparation of a Class A Fusible Toners using MethylMethacrylate and Butyl Acrylate

A 2-liter jacketed reaction vessel is charged with water (787.65 g)purified using milliQ system of purified water manufactured by MilliporeCorporation. The reactor is heated to 60° C. under positive pressure ofnitrogen. A syringe is filled with 106.64 g of 1.49% aqueous solution ofVA 440 (2,2′-Azobis(N,N′-dimethyleneisobutyramidine) dihydrochloride,(WaKo Pure Chemical Industries Ltd., Japan). A graduated addition funnelis filled with Noigen 10 (Montello Company, Tulsa, Okla.), (5.04 g),butyl acrylate (40.01 g), methyl methacrylate (60.10 g), and iso octylmercaptopropionate (0.78 g) and is fitted onto the reactor. One tenth ofeach of the solutions in both the syringe and the graduated cylinder isadded every 15 minutes until the addition is complete.

Heat is supplied and stirring is continued for 7 hours after theadditions are complete. The resulting emulsion is then filtered througha sequence of filters according to the following procedures. Four 11 μmWhatman filter papers are used to filter 500 ml of solutions. Six 2.7 μmGF/D Whatman filters are needed to filter the entire solution. Water wasevaporated off the resulting milky dispersion to furnish white powder ofthe toner material. Subsequently the powder was ground using a choice ofair jet milling or cryogenic or mechanical grinding, and classified toproduce powder of a 10μ average particle size. The glass transitiontemperature of Polymer A is 25-28° C. The toners were prepared by usingnormal methods for preparing electrography toners in which colorants areadded to the polymer followed by mixing by grinding in ball mill with orwithout a liquid, high shear mixing under heat, or co-extruding underheat. Additionally, the materials are ground by cryogenic or airjetmilling as necessary, and classified as described above. Furtheradditives such as copy charge agents available from Clariant Corporationwere added for electrostatic deposition. Pigment Carbon Black FW18,available from Degussa-Hules Corporation, Pigment Red 122 available formSun Chemical, or Pigment Blue 15, available from Sun Chemical, Amelia.Ohio, are used to prepare Black, Magenta and Blue toners respectively.

Example 2 Preparation of Class B Colored Toners using Styrene and MethylMethacrylate

Another fusible polymer is synthesized using styrene, methylmethacrylate, and a polymerizable surfactant in the following manner. A2L jacketed reaction vessel is heated to 60° C. under nitrogen andcharged with 393.4 g of water purified using MilliQ system. Organiccomponents Noigen 10 (2.5 g), styrene (30 g), methyl methacrylate (20g), and CTA (iso octyl mercaptopropionate) (0.375 g) are transferred toa glass syringe. The initiator solution is prepared by dissolving VA 440(2,2′-Azobis(N,N′-dimethyleneisobutyramidine) dihydrochloride (0.796 g)in MilliQ water (52.9 g). The reaction is performed by addition of 10%of each of the solutions every 15 minutes. The heating and stirring iscontinued for 7 hours after additions are complete. The emulsion isfiltered using following filters, 4, 11 μm Whatman, 3, 20 um msi withWhatman gf/d 2.7 um pre-filter, 1, 5 μm msi with Whatman gf/d 2.7 umprefilter to give a polymer emulsion. Water was evaporated off theresulting milky dispersion to fumish white powder of the toner material.Subsequently the powder was ground using a choice of airjet milling orcryogenic or mechanical grinding, and classified to produce powder of a10μ average particle size. The glass transition temperature of Polymer Bis 95-105° C. The toners were prepared by using normal methods forpreparing electrography toners in which colorants are added to thepolymer followed by mixing by grinding in ball mill with or without aliquid, high shear mixing under heat, or co-extruding under heat.Additionally, the materials are ground by cryogenic or air jetmilling ifnecessary, and classified as described above.

Pigment Carbon Black FW18, available from Degussa-Hules Corporation,Pigment Red 122 available form Sun Chemical, or Pigment Blue 15,available from Sun Chemical, Amelia, Ohio, are used to prepare Black,Magenta and Blue toners respectively.

Example 3

Testing Compositions

The results in the tables in Example 6 shows the type of toners used totest the invention using polymers synthesized by the above procedures.All the clear fluids are filtered through 5 micron nylon filtersavailable from Micron Separations, Inc. The clear immobilizing fluidsare filled in HP 2000C pens and warmed to 60° C. before printing. Thetoners were deposited using a cartridge from HPLaserjet 4L laserprinters, modified to work in series with a HP2000C inkjet printer. Thefollowing formulation of immobilizing fluid was used in the experiments.2-Pyrrolidine 10.0 g 1,5 Pentanediol 10.0 g Poly(2-ethyl-2oxazoline) 5.0g Water 64.5 g Multranol 4012 0.5 g TetraEthylene Glycol 10.0 gIn method A, the toner was deposited immediately after the inkjetprinting by a suitable means, either mechanical or electrostatic, andfused. In method B of printing the toner was deposited before printingby a suitable means, followed by inkjet printing, and nonwetted tonerwas removed from print, either by electrostatic or mechanical means andthen the prints were fused to produce permanent images. The printquality and definition was much improved as compared to hydrophobictoners.

Example 4

Permanence Testing: Procedures

The smear resistance which serves as a measure of mechanical andchemical (solvent) abrasion is measured by the amount of transfer ofcolor in milli optical density (mOD) units measured using MacBeth RD918optical density meter (available from MacBeth, a division of KollmorgenInstruments Corporation, New Windsor, N.Y.). After running basic(fluorescent) highlighters twice over a set of bars printed using an inkjet printer containing the respective inks.

The permanence of images produced by electrophotography (laser printingor copying), show the least transfer and lowest mOD numbers. Since theMacBeth instrument reports mOD units of transferred color in thisexperiment, the lower number indicates less transfer. Therefore, thelower numbers indicate better performance. The markers used for thispurpose are available from Sanford corporation or any office supplycenter under the name ‘Major Accent’ (read through highlighting marker)and ‘fluorescent’ (alkaline highlighting marker).

The tables below show comparative values of some of the commerciallyavailable transfer obtained from such smear tests.

As can be seen in Tables 1-3, both polymers A and B of the instantinvention produced comparable results. The two papers used were Gilbertbond (GBND) and Stora Papyrus MultiCopy (PMCY), available commercially.

Paper's propensity to absorb moisture because of the hydrophilic natureof the cellulose from which it is made has considerable implications forits behavior with various ink formulations. Paper in an ambient relativehumidity of 50% can contain up to eight weight percent water. Thismoisture can become the controlling factor in the performance of thepaper as a substrate in both electophotography and inkjet printing.

Example 5

Results of Smear Resistance Measurement (Values in mOD) TABLE 1Comparison of Commercial Cyan Inkjet Inks and Cyan Toners of InventionProcess (Numbers are in mOD units) GBND PMCY C1893A Commercial Cyan Inkfor Design Jet 551 544 Class A Toner with Blue 15 and Method A 0 10Class A Toner with Blue 15 and Method B 0 5 Class B Toner with Blue 15and Method A 0 5 Class B Toner with Blue 15 and Method B 0 8

TABLE 2 Comparison of Commercial magenta Toners and Invention Process(Numbers are in mOD units) GBND PMCY C1894A Commercial Magenta Ink forDesignJet 385 684 Class A Toner with Red 122 and Method A 0 6 Class AToner with Red 122 and Method B 0 5 Class B Toner with Red 122 andMethod A 0 5 Class B Toner with Red 122 and Method B 0 8

TABLE 3 Comparison of Commercial Black Inkjet Inks and Toners ofInvention Process (Numbers are in mOD units) GBND PMCY HP51645ACommercial Black Ink for 800 486 765 Class A Toner with CB FW 18 andMethod A 0 10 Class A Toner with CB FW 18 and Method B 0 12 Class BToner with CB FW 18 and Method A 0 5 Class B Toner with CB FW 18 andMethod B 0 8

TABLE 4 Laser Printer Testing Alkaline Acid CDCY GBND PMCY PNAT UCJTCDCY GBND PMCY PNAT UCJT NA NA NA NA NA NA NA NA NA NA 1 4 0 2 0 0 0 0 00

TABLE 5 Mita Laser Copier Testing Alkaline Acid CDCY GBND PMCY PNAT UCJTCDCY GBND PMCY PNAT UCJT NA NA NA NA NA NA NA NA NA NA 0 1 0 0 0 0 0 0 00

It can be seen that the permanence testing results of the instantinvention, using a variety of hydrophilic toners (Tables 1-5) exhibitmuch better permanence as compared to images produced by other inkjetprinters, and much closer to electrographic printers. The mOD values arefor current state of the art inkjet printers are consistently greaterthan 300.

It is clear that this invention process and materials combines thepermanence of electrophotography with the desirable features of inkjettechnology.

1-28. (canceled)
 29. An image on a substrate comprising discrete areasof inkjetted clear fluid and electrostatic toner comprising hydrophilicpolymers, the image being fused onto the substrate and discrete areassubstantially free of said inkjet ink and electrostatic toner.
 30. Theimage of claim 29 wherein said substrate is plain paper.
 31. The imageof claim 29 wherein said substrate is a transparency.
 32. The image ofclaim 29 wherein said image is created by the steps of: charging saidpaper with a given polarity; ink-jet printing a fluid onto said paper;exposing said paper from (b) to a clear toner having a polarity the sameas said paper in step (a); subjecting said paper from step (c) tofusing.
 33. A printing system comprising: an inkjet printing engine forinkjetting clear fluid; a developer mechanism for applying electrostatictoner comprising hydrophilic monomers; a charging unit; and a fuser. 34.A printing system of claim 33 wherein said inkjet printing engine is athermal inkjet printer.
 35. A printing system of claim 33 wherein
 35. Aprinting system of claim 33 wherein said charging unit is a corotron.36. A printing system of claim 33 wherein said developing mechanismcomprises a charged roller, a clear toner hopper, stirrer, wiper blade,and a source of AC/DC voltage biases.